Patent GB-344584-A (GB)
Title: Improvements in and relating to welding apparatus
IPC: B21C37/08
Filed: 1930-01-04
Abstract: 344,584. Uniting by fusion. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Chapman, V. J.; 25, Lakewood Avenue, Schenectady, New York, U.S.A.) Jan. 4, 1930, No. 403. Convention date, Jan. 5, .1929. [Class 83 (iv).] In making tubular structures such as tank shells with longitudinally-welded joints, a bent sheet with overlapping edges is placed in a welding machine with one edge against one side of members for locating the edges in the path of travel of the welding agency, and the other edge is withdrawn and held against the other side of the members so as to space the edges at the desired distance apart, whereupon the edges are clamped and the members removed prior to welding the seam. A tank shell 1 may be supported with its edges between clamping members 2, 3, 4 connected to each other at one end and suspended from vertical supports beneath a fusible electrode carried by a slide. Pivoted to brackets 11 secured to the ends of blocks 19, 20 on the members 2, 3 are weighted latches 12 each having one of a number of blades 13 of various thicknesses for engaging between the edges of the seam to position them in alignment with the electrode and at the required distance apart. When the edges have been positioned the parts are clamped by raising the backing member 21 preferably by distension of the hose 22 as described in Specification 246,795, [Class 83 (iv), Metals, Working], and the positioning members are moved about their pivots into inoperative position so that welding may be effected throughout the line of the joint without obstruction. The tank shell consists of a scroll, one edge of which is first positioned by the blades, the other edge being then removed from the position shown in Fig. 4 and placed against the other side of the blades and the parts then operated as previously described. In case of very thin parts which require very thin spacing blades, a taperended blade 13, Fig. 7, may be used for positioning and spacing purposes and is pushed upwards just prior to clamping so that its feathered edge spaces the edges the required distance apart. The use of thin blades is thus avoided. The members 2, 3, 4 may be connected at their centre so as to provide a set of clamps at each side thereof for operating on a pair of blades in turn. In this case a pair of positioning members for each blank is used consisting of blades 13 connected to semicircular members 25, which may be swung back about pivots 26 after centring so that the welding head may be traversed along the whole line of both blanks without vertical adjustment. The members may be operated by an air or other fluid pressure cylinder 31 controlled together with the hose 22 by a valve 32. The centring device may consist of a portable attachment with lifting handle 37, and comprising a body 33a to fit in between the clamps on the members 23, 24 or passing through a hole in the structure and having a movable centring member 35 formed on a headed pin 34. Specification 221,890, [Class 83 (iv), Metals, Working], is also referred to. The Specification as open to inspection under Sect. 91 (3) (a) states that one of the members of each pair, Fig. 8, may be independently operated by hand so that a previously tack-welded shell may be centred prior to welding ; in this case, one end of the shell is first centred by one member and the blank then warped until another portion of the seam is engaged by the second member. This subject-matter does not appear in the Specification as accepted.